1. Field of the Invention
The present invention relates generally to medicament dispensers. More particularly, the invention concerns a dispenser for use in controllably dispensing a liquid medicament from a reservoir disposed within the housing of the dispenser. The reservoir is typically filled using a medicament vial that is coupled with the dispenser housing by a novel polarity adapter.
2. Discussion of the Prior Art
A number of different types of medicament dispensers for dispensing medicaments to ambulatory patients have been suggested. Many of the devices seek either to improve or to replace the traditional gravity flow and hypodermic syringe methods which have been the standard for delivery of liquid medicaments for many years.
The prior art gravity flow methods typically involve the use of intravenous administration sets and the familiar bottle suspended above the patient. Such methods are cumbersome, imprecise and require bed confinement of the patient. Periodic monitoring of the apparatus by the nurse or doctor is required to detect malfunctions of the infusion apparatus.
For those patients that require frequent injections of the same or different amounts of medicament, the use of the hypodermic syringe method of delivery is common. However for each injection, it is necessary to first draw the injection dose into the syringe, then check the dose and, after making certain that all air has been expelled from the syringe, finally, inject the dose. This cumbersome and tedious procedure creates an unacceptable probability of debilitating complications, particularly for the elderly and the infirm.
One example of the urgent need for an improved liquid delivery device for ambulatory patients can be found in the stringent therapeutic regimens used by insulin-dependent diabetics. The therapeutic objective for diabetics is to consistently maintain blood glucose levels within a normal range much as the normally functioning pancreas would do by secreting a very low level of extremely fast-acting insulin at a basal rate into the blood stream throughout the day and night. As will be appreciated from the discussion which follows, the apparatus of the present invention is uniquely suited to provide precise fluid delivery management at a low cost in those cases where a variety of precise dosage schemes are of utmost importance.
An additional aspect of the apparatus of the present invention is the provision of novel fill means for filling the reservoir of the device using a conventional medicament vial having a pierceable septum. An important feature of this fill means is a novel polarity adapter that is used to operably interconnect the medicament vial with the delivery device. In this regard, the polarity adapter is preferably fixedly connected to a standard medicament vial to provide a "keyed fitting" for the vial to insure that the fluid reservoir of the fluid dispenser can be filled only with the proper medicament. More particularly, with the polarity adapter connected to the drug vial, the novel design of the dispenser system is such that the user can connect the drug vial and polarity adapter only to a dispenser system having a delivery profile appropriate for the delivery to the patient of the particular drug contained within the medicament vial.
Because the embodiments of the invention described herein comprise improvements to the devices described in U.S. Ser. Nos. 08/991,123 filed Dec. 16, 1997, and Ser. No. 08/606,090 filed Feb. 23, 1997, application Ser. No. 08/991,123 is hereby incorporated by reference in its entirety as though fully set forth herein Similarly, application Ser. No. 08/606,090 is also hereby incorporated by reference in its entirety as though fully set forth herein.
Also helpful to a complete understanding of the present invention is an earlier filed application by the present inventor, which is identified by the Ser. No. 08/541,184. This application, which was filed on Oct. 11, 1995 is also incorporated by reference in its entirety as though fully set forth herein.
With regard to the prior art, one of the most versatile and unique fluid delivery apparatus developed in recent years is that developed by one of the present inventors and described in U.S. Pat. No. 5,205,820. The components of this novel fluid delivery apparatus generally include: a base assembly, an elastomeric membrane serving as a stored energy means, fluid flow channels for filling and delivery, flow control means, a cover, and an tillage which comprises a part of the base assembly.
The present invention seeks to significantly improve over the prior art by providing a fluid delivery device having novel filling means for filling the fluid reservoir of the device only with a class of drug that is compatible with the delivery profile of the delivery device. This important safety feature is accomplished through the use of a unique polarity collar that is attached to the vial and is uniquely configured so that it will only mate with a fluid delivery device having the appropriate medicament delivery profile.